prerender_test_server.py: bind to loopback interface

chrome/browser/prerender/tools/prerender_test_server/prerender_test_server.py

 #!/usr/bin/env python
 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # A local web server with a copy of functionality of
 # http://prerender-test.appspot.com with a DISABLED check whether Prerendering
 # is working.
 
 import BaseHTTPServer
@@ skipping 36 matching lines @@
     self.send_response(200)
     self.send_header('Content-type', mime_type)
     self.send_header('Cache-Control', 'no-cache')
     self.end_headers()
 
 def main(argv):
   parser = argparse.ArgumentParser(prog='prerender_test')
   parser.add_argument('-p', '--port', type=int, default=8080,
                       help='port to run on (default = %(default)s)')
   args = parser.parse_args(argv)
+  server_name = 'localhost'
 
-  s = BaseHTTPServer.HTTPServer(('', args.port), Handler)
+  s = BaseHTTPServer.HTTPServer((server_name, args.port), Handler)
   try:
-    print("Listening on http://localhost:%d/" % args.port)
+    print('Listening on http://{}:{}/'.format(server_name, args.port))
     s.serve_forever()
     return 0
   except KeyboardInterrupt:
     s.server_close()
     return 130
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))